Select incorrect pairing.

Options

A. Hetersomes-Sex chromosomes
B. Lampbrush chromosomes-Diplotene bivalents
C. Polytene chromosomes - Oocytes of amphibians
D. Heterochromatin - Darkly stained region of chromosome

Answer

To solve the question of selecting the incorrect pairing, we will analyze each option provided in the question step by step.

### Step-by-Step Solution:

1. **Understanding Heterozome**:
- Heterozome refers to sex chromosomes, which are different from each other. In humans, these are the X and Y chromosomes.
- **Conclusion**: The first option is correct because heterozomes are indeed the sex chromosomes (X and Y).

2. **Understanding Lamb Brush Chromosome**:
- Lamb brush chromosomes are found during the diplotene stage of meiosis and are characteristic of large oocytes in many vertebrates.
- **Conclusion**: The second option is also correct since lamb brush chromosomes are indeed found in the large oocytes of many vertebrates during the diplotene stage.

3. **Understanding Polytene Chromosome**:
- Polytene chromosomes are a type of chromosome that is found in certain organisms, most notably in Drosophila (fruit flies), and not in amphibians.
- The statement claiming that polytene chromosomes are found in the oocytes of amphibians is incorrect.
- **Conclusion**: The third option is incorrect because polytene chromosomes are not found in amphibians; they are found in Drosophila species.

4. **Understanding Heterochromatin**:
- Heterochromatin refers to the densely packed form of DNA in chromosomes that appears darkly stained under a microscope. It contrasts with euchromatin, which is lightly stained and less condensed.
- **Conclusion**: The fourth option is correct as heterochromatin is indeed the darkly stained region of chromosomes.

### Final Conclusion:
The incorrect pairing is the third option: **Polytene chromosome which is said to be oocyte of Amphibia**.

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